Gas-blast circuit interrupters with closed recirculating system having gas filtering means



Oct. 26, 1965 w. M. LEEDS 3,214,553

7 GAS-BLAST CIRCUIT INTERRUPTERS WITH CLOSED REGIRCULATING SYSTEM HAVING GAS FILTERING MEANS 4 Sheets-Sheet 1 Original Filed March 27, 1961 INVENTOR Winthrop M. Leeds ATTORNEY Mam-- Oct. 26, 1965 w M LEEDS 3,214,553

GAS-BLAST CIRCUIT INTERIRUP'IERS WITH CLOSED RECIRGULATING SYSTEM HAVING GAS FILTERING MEANS Oct. 26, 1965 w. M. LEEDS 3,214,553

GAS-BLAST CIRCUIT INTERRUPTERS WITH CLOSED RECIRCULATING SYSTEM HAVING GAS FILTERING MEANS Original Filed March 27. 1961 4 Sheets-Sheet 3 VOLTAGE DIVIDING CAPACITOR HIGH PRESSURE Oct. 26, 1965 LEEDS 3,214,553

W. M. GAS-BLAST CIRCUIT INTERRUPTERS WITH CLOSED RECIRCULATING SYSTEM HAVING GAS FILTERING MEANS Original Filed March 27. 1961 4 Sheets-Sheet 4 VOLTAGE DIVIDING CAPACITOR HIGH PRESSURE United States Patent 3,214,553 GAS-BLAST CIRCUIT INTERRUPTERS WITH CLOSED RECIRCULATING SYSTEM HAV- ING GAS FILTERING MEANS Winthrop M. Leeds, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Continuation of application Ser. No. 98,632, Mar. 27, 1961. This application July 9, 1964, Ser. No. 384,021 9 Claims. (Cl. 200-148) This application is a continuation of my patent application filed March 27, 1961, Serial No. 98,632, now

abandoned.

This invention relates generally to gas-blast circuit interrupters, and, more particularly, to filtering and purifying means for the arced gas which is used to eifect interruption of the established arcing. Certain aspects of the instant invention are set forth and claimed in divisional application filed February 7, 1964, SN. 343,371, and assigned to the assignee of the instant application.

A general object of the present invention is to provide an improved compressed-gas circuit interrupter of the type employing as an arc-extinguishing medium a gas of relatively high dielectric strength and an elficient arc extinguisher, such as sulfur-hexafluoride (SF gas, selenium-hexafiuoride (SeF gas, (CF SF and other gases which may have active products of decomposition following their use as arc-extinguishing gases.

A more specific object of the present invention is to provide an improved compressed-gas circuit interrupter utilizing a substantially closed gaseous system, in which the gas is repeatedly reused, and in which novel filtering means are provided to purify the gas prior to its subse quent ejection into the general interior of the circuit-breaker structure.

Power circuit breakers using SP gas, for example, for insulation and are interrupting have been built in many forms: single-bushing types, live-tank types, dead-tank types, etc., all showing excellent performance possibilities. By proper choice of insulating materials, deterioration from the effects of active gas products of arcing has been avoided, with containers of activated alumina powder being provided to gradually purify the gas. Metallic fluoride powders are also formed by arcing at the contacts in SP but these are insulating when dry and normally give no trouble.

Carbon particles from gases such as CF and C F should also be removed to prevent their deposit upon insulating surfaces.

However, maintenance of breakers may involve exposure of personnel to slightly toxic vapors, if breakers are opened immediately after heavy fault interruptions. Also, on humid days, the fluoride powders absorb moisture quickly, and very complete cleaning of all insulating surfaces becomes essential.

The present invention is intended to eliminate such maintenance difiiculties by directing all arced gases into a metal chamber where no insulation stressed by voltage would be present. Then an activated alumina powder filter or a mesh filter is provided, through which the gas must flow before it can reach insulating surfaces. Thus, reactive vapors and powders are removed before the gas is returned to the rest of the breakers for reuse.

Accordingly, it is a further object of the present invention to provide improved compressed-gas circuit-breaker structures, in which maintenance problems are reduced by collecting all of the arced gas following its use as an arc extinguisher, and immediately purifying, or filtering such arced gas prior to its subsequent release into the general interior of the breaker structure.

Since the integrity of the insulation to ground is of paramount importance, fairly inaccessible parts such as rods, tubing and porcelain surfaces in the supporting columns of the breaker are particularly important to protect from fluoride powder accumulation. This means that the screening action of the filter in taking out solid particles is its primary function. If purification of the gas is not complete in this filter on the downstream side of the interrupter, additional purification will take place in the filter provided ahead of the compressor used to fill the high-pressure gas reservoir.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjuction with the drawings, in which:

FIGURE 1 is a longitudinal vertical sectional view taken through a single-bushing type of circuit interrupter illustrating an application of the invention, with the contact structure being illustrated in the partially open-circuit position;

FIG. 2 is a vertical sectional view taken through a compressed-gas circuit interrupter, again the contact structure being illustrated in the partially open-circuit position;

FIG. 3 is a longitudinal vertical sectional view taken through a still further modified type of compressed-gas circuit interrupter, again the contact structure being illustrated in the partially open-circuit position; and,

FIG. 4 is a modified type of filtering arrangement for the breaker illustrated in FIG. 3.

Referring to the drawings, and more particularly to FIGURE 1 thereof, the reference numeral 1 generally designates a puffer-type circuit interrupter of the singlebushing type. Generally, the circuit interrupter 1 comprises a terminal bushing 2, a pulfer-type interrupting unit 3 fixedly secured to the end 4 of the bushing 2, a surrounding casing 5, and preferably, a line-terminal cap structure 6.

The terminal cap structure 6 generally includes a perforated partition plate 7, having a plurality of perforations 7a provided therein, a filter element 8, which may comprise suitable fine-mesh screening and activated alumina powder, and an outer line cap 9 with a terminal stud portion 10.

Associated with the outer extremity 11 of the terminal bushing 2 is a second line terminal connection 12, to which the other line connection may be made.

Passing centrally through the terminal bushing 2 is a conductor stud 13, which preferably has threadedly secured thereto a relatively stationary piston 14. Slidable over the piston 14 is a movable puffer cylinder 15 carrying therewith an insulating orifice chamber mem-' ber 16. A tubular relatively stationary contact 17 extends through the orifice opening 18 of the orifice chamber 16, and makes engagement with a plurality of segmental fingers 19, constituting a portion of a movable contact structure 20. In addition, preferably a movable arcing horn 21 is provided, to which the are 22 may attach during the opening operation, as shown in FIG. 1.

Pivotally connected, as at 23, to the external side of the puffer cylinder 15 is an insulating operating rod 24. The operating rod 24 is additionally pivotally connected, as at 25, to a crankarm 26 alfixed to a rotatable drive shaft 27. Preferably, the drive shaft 27 extends, by way of a sealed opening through the side wall of the mechanism housing 28, and is actuated externally of the mechanism housing 28 by an externally-located crankarm 29, which is pivotally connected, by a pivot pin 30, to an operating rod 31. The operating rod 31 may be actuated by any suitable operating mechanism disposed within an operating mechanism housing 32 supported upon a base 33. Also extending upwardly from the base 33 is a grounded framework 34 which supports the grounded mechanism housing 28 and the central portion of the terminal bushing 2.

As shown in FIGURE 1, a pair of current transformers 35 are provided, encircling the central portion of the terminal bushing 2, and providing a measure of the current passing through the circuit interrupter 1. As well known by those skilled in the art, the current transformers 35 are employed in connection with protective relaying equipment to effect opening of the circuit breaker 1 should fault conditions be encountered.

In the closed-circuit position of the interrupter 1, the electrical circuit therethrough comprises the line cable L line terminal 12, metallic end cap 11, conducting terminal stud 13, relatively fixed piston 14, conducting putter cylinder 15, contact support plate 36, movable contact fingers 19, relatively stationary contact 17, perforated partition plate 7, line terminal cap 9, and line connection to line cable L To effect the opening operation of the circuit interrupter 1, suitable means, not shown, are effective within the mechanism compartment 32 to effect downward opening movement of the operating rod 31. Through the linkage comprising crankarms 26, 29 and operating rod 24, the movable pufier cylinder is actuated toward the left, as viewed in FIGURE 1, thereby compressing the gas within the region 37, and forcing the same through the orifice opening 18 and through stationary tubular contact 17, past the check valve 38 and into the exhaust chamber 39. It is evident that the gas, after passing into the exhaust chamber 39 must traverse the filtering material 8 prior to its passage through the perforations 7a and back into the general interior 40 disposed within casing 5 for subsequent reuse.

The provision of the check valve 38 spring-biased slightly to a closed position, prevents a return of the gas out of exhaust chamber 39 through the tubular stationary contact 17. As pointed out above, it is desirable to completely filter all of the arced gas prior to its subsequent reuse and contact with insulating surfaces. In the construction illustrated in FIG. 1, it is obvious that substantially all of the arced gas will be compelled to pass through the tubular stationary contact 17, through the check valve 38, and into exhaust chamber 39. Prior to its subsequent reuse, it is compelled to pass through the filtering material 8, where the metallic fluoride powders will be extracted together with any active products of decomposition.

FIGURE 2 illustrates a type of circuit-interrupting structure embodying the principles of the present invention. It will be noted that here there is provided a live metallic tank 42 filled with high-pressure gas, for example sulfur-hexafluoride (SP gas at 150 p.s.i. Extending laterally through the live metallic high-pressure tank 42 is a pair of oppositely-disposed terminal bushings 43, 44, supporting relatively stationary contact posts 45 within the general interior 46 of the tank structure 42. The terminal bushings 43, 44, preferably comprise insulating weatherproof casings 47 and outer terminal cap portions 48, 49.

Cooperable with the inner ends of the relatively stationary contact posts 45 is a substantially U-shaped bridging structure, generally designated by the reference numeral 50, and comprising a pair of vertically-extending conducting operating rods 51, interconnected adjacent their lower ends by a conducting transverse bridging member 52. An insulating operating rod 53 extends interiorly of an upstanding supporting insulating column 54, and serves to eifect upward closing and downward opening movement of the pair of conducting operating rods 51 in an obvious manner.

It is desirable to effect a sealed connection between the operating rod 51 and the wall of the live tank 42. For this purpose, preferably metallic bellows 55 are provided, being sealed, as by a brazed connection to the tank 42, and also being sealed, as bya brazed connection to a plate 56, which, in turn, is atfixed to the conducting operating rod 51 and movable therewith.

Disposed interiorly of the live tank structure 42 is a blast-valve housing chamber 57 having a pair of orifice openings 58 associated therewith. A movable blast valve 59 has a pivotal linkage 60 engaged by a drive-pin 61, affixed to, and movable with, the left-hand conducting rod 51, as viewed in FIG. 2. The blast valve 59 is guided by a moving guide 62 slidable within a guide housing 63 aflixed by a pair of supports 64 to the blast valve housing 57. As shown, a compression spring 65 biases the guide 62, and consequently the blast valve 59 to the closed position.

In the closed-circuit position of the circuit interrupter 66, the electrical circuit passing therethrough generally includes line terminal connection 48, relatively stationary contact post 45, finger contacts 67, conducting operating rod 51, conducting transverse member 52, right-hand conducting operating rod 51, right-hand relatively movable contact finger 67, right-hand contact post 45, from whence the circuit extends through the right-hand terminal bushing 44 to the other terminal connection 49.

During the opening operation, suitable means, not shown, is operable to effect downward opening movement of the insulating operating rod 53. This will bring about corresponding downward opening movement of the transverse conducting member 52, and consequently the conducting operating rods 51, which are secured thereto.

The downward opening movement of the conducting operating rods 51 will effect separation between the movable contact fingers 67 and the inner extremities of the contact posts 45 to draw arcs therebetween. Preferably, one of the contact fingers 67a is made slightly longer than the other contact finger 67, and has an arcresisting tip portion 68 associated therewith.

Simultaneously with the downward opening movement of the left-hand conducting operating rod 51, the drivepin 61 associated therewith effects, through the linkage 60 upward opening movement of the blast valve 59 to permit a blast of gas to pass out of the valve housing 57 and into a metallic exhaust chamber 69. Filtering material, such as fine wire mesh and activated alumina 70 is preferably disposed within the exhaust cylinder 69, and this forces all of the exhaust gases to pass therethrough prior to subsequent passage through perforations 7'1 and into the general interior 72 within the upstanding insulating column 54. The sulfur-hex-afluoride gas within the insulating column 54 is preferably at a pressure of substantially 30 psi.

The opening of the blast valve 59, downstream of the orifice opening 58, will cause the radially infiowing blast of gas about the stationary contact post 45 to carry the are 73 to an arcing-horn portion 74, which constitutes a portion of the guide cylinder 63. As shown in FIGURE 2, the two serially related arcs 73, extending through the orifice openings 58, are subjected to a radial inward blasting of gas, which passes downwardly within the valve housing 57 and is exhausted into the lower exhaust chamber 69. I

As was the case with the circuit interrupter 1 of FIG. 1, it will again be observed that all of the arced gas is compelled to pass through the metallic exhaust chamber 69, and through the filtering material 70 prior to its subsequent reuse.

Suitable compressor means, not shown, are operable to extract the gas within the general interior 72 of the insulating column 54, which is substantially at 30 p.s.i., and to recompress this gas to the high-pressure value of 150 psi, from whence it is fed from the compressor upwardly by way of the feed tube 75 from ground potential and back into the upper live tank 42 for subsequent reuse.

From the foregoing description of the circuit interrupter 66 of FIG. 2, it will be apparent that again all of the gas used during interruption of the arcs 73 will be compelled to pass through the filtering material 70 prior to its subsequent reuse.

From the foregoing, it will be apparent that in the circuit interrupter 66, illustrated in FIG. 2 of the drawings, that there is provided a novel construction with a highpressure reservoir 42 at high potential, with terminal bushings 43, 44 at each side of the tank. Pulling open the contacts 67 operates a blast valve 59 on the exhaust side of the flow channels 58. The exhaust gases go through the filter 70 in the metal exhaust chamber '69 and finally into the supporting porcelain column 54. The low-pressure gas from the column 54 is recompressed and fed up an insulating pipe 75 to the high-potential high-pressure tank 42.

FIGURE 3 illustrates a still further modified type of circuit-interrupting structure 77. Generally, the circuit interrupter 77 includes a grounded horizontally-extending metallic tank 78, into which extend a pair of terminal bushings 79, 80, having tubular conductor studs 81. There is thus provided a passageway 82 through each conductor stud 81.

Supported adjacent the interior ends of the terminal bushings 79, 80 is a bridging arc-extinguishing assemblage, generally designated by the reference numeral 83. The arc-extinguishing assemblage 83 includes a substantially centrally-located high-pressure tank 84, which supports a pair of relatively stationary contacts 85 cooperable with movable perforated tubular contacts 86. A pair of serially-related arcs 76 are established between the movable tubular contacts 86 and the relatively stationary contact fingers 85. Stationary insulating arcing chambers 87 are provided to dire-ct the gas released by opening of the blast valve 88. As shown, the blast valve 88 is actuated by a cam 89 provided on a connecting rod 90, constituting a part of the linkage 91 effecting simultaneous opening and closing movement of the two movable contacts 86.

Preferably, a pair of accelerating opening springs 92 are provided to bias the movable contact structures toward the open position, as shown. To effect the closing of the contact structure, an insulating pull rod 93 is actuated, through a crankarm 94, to effect rotation of the crankshaft 95. The crankarm 94 is affixed to a rotatable drive shaft 96, extending laterally through a mechanism housing 97, and is rotated externally of the tank 78 by any suitable means, not shown.

A feed tube 98, formed of an insulating material, is provided to feed high-pressure gas from an externallyprovided high-pressure reservoir back into the centrally disposed high-pressure chamber 84.

In the closed-circuit position of the interrupter 77, the circuit therethrough extends from terminal cap 99 through the conducting tubular conductor stud 81, metallic exhaust chamber :100, by means of a sliding connection 101 with movable tubular contact 86, contact fingers 85, then through housing 84, and to the right-hand interrupting unit 102 in a similar manner, and through right hand terminal bushing 80 to line connection 104.

To effect the opening operation of the interrupter 77, the drive shaft 96 is unlatched by means, not shown, and this permits the two accelerating opening springs 92 to effect opposing movement of the pair of tubular movable contacts 86 from the relatively stationary contact fingers 85. Simultaneously with this movement, the cam portion 89 effects opening of an exhaust valve 105 to dump the pressure within a region 106 below the blast valve 88. This will open the blast valve 88 and permit gas to be ejected from the general interior 107 of the high-pressure chamber 84, and out through orifice openings 108 and through the movable tubular contacts 86 into the exhaust chambers 100. The exhausting gas will be forced, from the exhaust chambers 100, upwardly through the tubular conductor studs 81 and through check valves 109 into relatively cool terminal-cap structures 110. Filtering material 111 is provided in the cap structures 110 and neces- 5 sitates that all of the arced gas will be compelled to pass" through the filtering material 111 before it is permitted to pass downwardly through the return passages 112, within the terminal bushings 79, to re-enter the interior 113 of the tank structure 78 through inlet openings 114 at the lower interior ends of the-terminal bushings 79, 80.

From the foregoing description, it will be apparent that again all of the arced gas, which is utilized during the interrupting operation, will be compelled to pass through the exhaust chambers 100, and upwardly through the tubular conductor studs 81 to pass through the filtering material 111 prior to its subsequent reuse within the tank structure 78. As was the case with the circuit interrupter 66 of FIG. 2, suitable compressor means are provided externally of the tank 78 to extract gas from the general interior 113 of the tank structure 78, and to recompress this relataively low-pressure gas to the highpressure value of, say 150 p.s.i., to cause its subsequent supply back into the high-pressure chamber 84.

From the above description, it will be apparent that the circuit interrupter 77, as illustrated in FIGURE 3, contains two interrupter units 102 per pole. The tank 78 is filled with sulfur-hexafluoride (SP gas at relatively low pressure, say 30 psi. However, relatively highpressure gas, say 150 p.s.i., is available in the central reservoir 84, with a blast valve 88 operated by a cam on the contact opening rod 90. The arcs 76 are blasted into hollow moving contacts 86, which direct the exhaust gases through hollow terminals 81 in the insulating terminal bushings 79, 80. The gas is put through filters 111 in the bushing caps before being returned to the main tank 78.

Although considerable laboratory data is available in regard to the reaction of SP by reason of analogy, it is believed that the same contaminating problem is present with gases such as SeF CF SF and SO F The filters are set forth in the above described circuit interrupter may be employed to remove carbon from certain gases, which give off carbon during circuit interruption. A few of such gases are C F the Freon gases, such as Freon 12 and C1 For the purpose of removing carbon, glass wool, paper, such as blotting paper, may be employed. By reason of such filtering of the carbonemitting gases, such gases will be in a condition for subsequent reuse without the deleterious effect of carbon being deposited upon insulating surfaces.

From the foregoing description, it will be apparent that the invention is particularly concerned with a gas-type of circuit interrupter comprising a closed gaseous system, wherein arced gas is collected and filtered, before being released to come into contact with high-voltage insulation.

It is to be noted that the casing 5 of FIG. 1, casing 54 of FIG. 2, and bushing casings 79 of FIGS. 3 and 4 constitute hollow structural members subjected to line-togroun-d voltage, constitute conduit parts of closed gaseous systems of the circuit breakers and, in addition assist in supporting the separable contact structures. The immediate extraction of the reactive products prior to depositing on the surfaces of such casings prevents line-toground flashovers.

Mechanical filtering of solid particles may take place immediately, whereas the chemical removal of the arced gases may take place at other locations within the breaker over a longer period of time. For instance in the modified structure of FIG. 4, screens alone may comprise the filter elements 111 whereas an activated alumina filter may be provided within the breaker tank 78 for the absorption of arcing gases over a larger period of time. This has the advantage of reducing back pressure Within the filter 111 where this is undesirable.

Although there have been illustrated and described specific interrupting structures, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications will readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

I claim as my invention:

1. In a gas-blast circuit interrupter having separable contact structure for establishing arc-ing and employing a substantially closed gaseous system for conserving and reusing the blasted gas, said interrupter having means for effecting separation of said separable contact structure within said substantially closed gaseous system and for blasting the established arc with gas, said interrupter also utilizing a gas which when exposed to arcing forms reactive products of decomposition at least momentarily, the combination therewith of means including an insulating hollow structural member for supporting at least a portion of said separable contact structure and serving as a conduit for arced gas, said insulating hollow structural member having the length thereof subjected to lineto-ground voltage and constituting a part of said substantially closed gaseous system, means including a metallic exhaust chamber disposed in near proximity to said separable contact structure and at the same potential as the separable contact structure in the closed-circuit position, and said metallic exhaust chamber containing a suitable filter material so as to effect immediate extraction of said reactive products from the arced gas prior to recirculation of the arced gas through said insulating hollow structural member for subsequent reuse.

2 The combination according to claim 1, wherein a tubular contact is utilized and the exhausted arced gas is forced through the tubular contact, and wherein the metallicexhaust chamber is disposed immediately rearwardly of said tubular contact.

3. A single-bushing type of circuit interrupter including a single terminal bushing, grounded supporting means for supporting said single terminal bushing intermediate the ends thereof, a puffer-type interrupting unit for blasting gas supported adjacent one end of said single terminal bushing having separable contact structure for estab lishing arcing, said contact structure including a relatively stationary tubular contact, said circuit interrupter employing a substantially closed gaseous system for conserving and reusing the blasted gas, means for effecting operation of said puffer-type interrupting unit and consequent separation of said separable contact structure within said substantially closed gaseous system, the operation of said puffer-type interrupting unit blasting the established arc with compressed gas, said circuit interrupter utilizing a gas which when exposed to arcing forms reactive products of decomposition at least momentarily, means including an insulating hollow structural member abutting said grounded supporting means at one end thereof and at least partially surrounding said putter-type interrupting unit, said hollow structural member supporting at least a portion of said separable contact structure adjacent the other end thereof, said insulating hollow structural member serving as a conduit for arced gas and having the length thereof subjected to line-to-ground voltage and constituting a part of said substantially closed gaseous system, means including a metallic exhaust chamber disposed in near proximity to said separable contact structure and supported by said other end of said hollow structural member, said metallic exhaust chamber being at the same potential as the separable contact structure, in the closed-circuit position, orifice means for directing substantially all of the arced gas through said relatively stationary tubular contact and into said metallic exhaust chamber, and said metallic exhaust chamber containing a suitable filter material so as to effect immediate extrac tion of said reactive products from the arced gas prior to recirculation of the arced gas through said insulating hollow structural member for subsequent reuse.

4, A single-bushing type of circuit interrupter including a single terminal bushing, grounded supporting means for supporting said single terminal bushing intermediate the ends thereof, a puffer-type interrupting unit for blasting gas supported adjacent one end of said single terminal bushing having separable contact structure for establishing arcing, said contact structure including a relatively sta tionary tubular contact, said circuit interrupter employing a substantially closed gaseous system for conserving and reusing the blasted gas, means for effecting operation of said puffer-type interrupting unit and consequent separation of said separable contact structure within said substantially closed gaseous system, the operation of said puffer-type interrupting unit blasting the established are with compressed gas, said circuit interrupter utilizing a gas which when exposed to arcing forms reactive products of decomposition at least momentarily, means including an insulating hollow structural member abutting said grounded supporting means at one end thereof and at least partially surrounding said puffer-type interrupting unit, said hollow structural member supporting at least a portion of said separable contact structure adjacent the other end thereof, said insulating hollow structural member serving as a conduit for arced gas and having the length thereof subjected to line-to-ground voltage and constituting a part of said substantially closed gaseous system, means including a metallic exhaust chamber supported by said other end of said hollow structural member, said metallic exhaust chamber supporting the relatively stationary tubular contact, said metallic exhaust chamber being at the same potential as the separable contact structure in the closed-circuit position, orifice means for directing substantially all of the arced gas through said relatively stationary tubular contact and into said metallic exhaust chamber, and said metallic exhaust chamber containing a suitable filter material so as to effect immediate extraction of said reactive products from the arced gas prior to recirculation of the arced gas through said insulating hollow structural member for subsequent reuse.

5. The combination in a high-power breaker of a grounded tank, a pair of terminal bushings having tubular conducting studs extending within said grounded tank and supporting a bridging arc-extinguishing assemblage therein, a high-pressure tank disposed intermediate the ends of said arc-extinguishing assemblage and supporting a palr of oppositely-extending relatively stationary contacts, a pair of oppositely movable tubular contacts cooper-able with the relatively stationary contacts to estab- 1311 a pair of serially-related arcs, and an exhaust chamber disposed adjacent the interior end of each tubular conductor stud for collecting the arced gas and causing it to flow out through the tubular conductor studs for cooling purposes, and means for recirculating arced gas through the terminal bushings and back into the general Interior of the tank.

6. The combination in a high-power circuit breaker of a grounded tank, a pair of vertically extending terminal bushlngs having tubular conducting studs extending within said grounded tanks and supporting a bridging arcextmguish ng assemblage therein, a high pressure tank disposed intermediate the ends of said arc-extingushing assemblage and supporting a pair of oppositelyextendmg relatively stationary contacts, a pair of oppositely movable tubular contacts cooperable with the relatively stationary contacts to establish a pair of seriallyrelated arcs, an exhaust chamber disposed rearwardly of each movable tubular contact and communicating with the lower ends of the tubular conductor studs, filtering means disposed adjacent the upper ends of the two terminal bushings, whereby the arced gas may be collected by the exhaust chambers and forced upwardly through the tubular conducting studs and through the filtering means prior to subsequent reuse within the general interior of the tank.

7. A compressed-gas circuit interrupter including a grounded metallic tank, a pair of vertically-extending spaced terminal bushings having tubular conductor studs extending downwardly within said grounded tank and supportmg a bridgingarc-extinguishing assemblage therein, each of said terminal bushings having an insulating bushing casing, a high-pressure tank disposed intermediate the ends of said arc-extinguishing assemblage and supporting a pair of oppositely-extending relatively stationary contact means, a pair of oppositely-movable tubular contact means cooperable with the relatively stationary contact means to establish a pair of serially-related arcs, a metallic exhaust chamber disposed adjacent the interior end of each tubular conductor stud and disposed rearwardly of the movable tubular contact means, filtering means disposed adjacent the upper end of each terminal bushing, means defining a return passage within each terminal bushing between the outer wall of the tubular conductor stud and the inner wall of the bushing casing, whereby substantially all of the arced gas may be collected within the exhaust chambers, forced upwardly through the tubular conductor studs and through the filtering means to eventually return downwardly through the return passages provided by the terminal bushings and into the general interior of the tank for subsequent reuse.

8. A compressed-gas circuit interrupter including a grounded metallic tank, a pair of vertically extending spaced terminal bushings having tubular conductor studs extending downwardly within said grounded tank and supporting a bridging arc-extinguishing assemblage therein, each of said terminal bushings having an insulating bushing casing, a high-pressure tank disposed intermediate the ends of said arc-extinguishing assemblage and supporting a pair of oppositely-extended relatively stationary contact means, a blast valve associated with the high-pressure tank, a pair of oppositely-movable tubular contact means cooperable with the relatively stationary contact means to establish -a pair of serially related arcs, a metallic exhaust chamber disposed adjacent the interior end of each tubular conductor stud and disposed rearwardly of the movable tubular contact means, filtering means disposed adjacent the upper end of each terminal bushing, means defining a return passage within each terminal bushing between the outer wall of the tubular conductor stud and the inner wall of the bushing casing, whereby substantially all of the arced gas may be collected within the exhaust chambers, forced upwardly through the tubular conductor studs and through the filtering means to eventually return downwardly through the return passages provided by the terminal bushings into the general interior of the tank for subsequent reuse, linkage means interconnecting the two movable tubular contact means for e c g e r s m lta motion, and c m me n associated with the linkage means for operating said blast valve associated with the high pressure tank.

9. In a gas-blast circuit interrupter having separable contact structure for establishing arcing and employing a substantially closed gaseous system for conserving and reusing the blasted gas, said interrupter having means for effecting separation of said separable contact structure within said substantially closed gaseous system and for blasting the established arc with gas, said interrupter also utilizing a gas which when exposed to arcing forms reactive products of decomposition at least momentarily, the combination therewith of means including a terminal bushing having an insulating hollow structural member for supporting at least a portion of said separable contact structure and serving as a conduit for arced gas, said insulating hollow structural member having the length thereof subjected to line-to-ground Voltage and constituting a part of said substantially closed gaseous system, means including a metallic exhaust chamber at the same potential as the separable contact structure in the closedcircuit position, and said metallic exhaust chamber containing a suitable filter material so as to effect immediate extraction of said reactive products from the arced gas prior to recirculation of the arced gas through said insulating hollow structural member for subsequent reuse.

References Cited by the Examiner UNITED STATES PATENTS 2,108,560 2/38 Kesselring 200-148 2,125,525 8/38 Thommen 200148 2,221,720 11/40 Prince ZOO-148 2,459,600 1/49 Strom 200-148 2,748,226 5/56 MacNeill et al 200-148 2,757,261 7/56 Lingal et al. 200-148 2,824,937 2/58 Strom 200l48 2,955,182 10/60 Caswell et al. 200-148 2,979,591 4/61 Friedrich 200-150 3,009,042 11/61 Schrameck et al. 200-148 FOREIGN PATENTS 1,136,382 12/56' France. 1,222,392 1/60 France.

KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, BERNARD A. GILHEANY,

Examiners. 

1. IN A GAS-BLAST CIRCUIT INTERRUPTER HAVING SEPARABLE CONTACT STRUCTURE FOR ESTABLISHING ARCING AND EMPLOYING A SUBSTANTIALLY CLOSED GASEOUS SYSTEM FOR CONSERVING AND REUSING THE BLASTED GAS, SAID INTERRUPTER HAVING MEANS FOR EFFECTING SEPARATION OF SAID SEPARABLE CONTACT STRUCTURE WITHIN SAID SUBSTANTIALLY CLOSED GASEOUS SYSTEM AND FOR BLASTING THE ESTABLISHED ARC WITH GAS, SAID INTERRUPTER ALSO UTILIZING A GAS WHICH WHEN EXPOSED TO ARCING FORMS REACTIVE PRODUCTS OF DECOMPOSITION AT LEAST MOMENTARILY, THE COMBINATION THEREWITH OF MEANS INCLUDING AN INSULATING HOLLOW STRUCTURAL MEMBER FOR SUPPORTING AT LEAST A PORTION OF SAID SEPARABLE CONTACT STRUCTURE AND SERVING AS A CONDUIT FOR ARCED GAS, SAID INSULATING HOLLOW STRUCTURAL MEMBER HAVING THE LENGTH THEREOF SUBJECTED TO LINETO-GROUND VOLTAGE AND CONSTITUTING A PART OF SAID SUBSTANTIALLY CLOSED GASEOUS SYSTEM, MEANS INCLUDING A METALLIC EXHAUST CHAMBER DISPOSED IN NEAR PROXIMITY TO SAID SEPARABLE CONTACT STRUCTURE AND AT THE SAME POTENTIAL AS THE SEPARABLE CONTACT STRUCTURE IN THE CLOSED-CIRCUIT POSITION, AND SAID METALLIC EXHAUST CHAMBER CONTAINING A SUITABLE FILTER MATERIAL SO AS TO EFFECT IMMEDIATE EXTRACTION OF SAID REACTIVE PRODUCTS FROM THE ARCED GAS PRIOR TO RECIRCULATION OF THE ARCED GAS THROUGH SAID INSULATING HOLLOW STRUCTURAL MEMBER FOR SUBSEQUENT REUSE. 